Coherence Transfer Pathways and Phase Cycles: The Decoding of a Pulse Sequence

✍ Scribed by McClung, R. E. D.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 411 KB
• Volume: 11
• Category: Article
• ISSN: 1043-7347
• DOI: 10.1002/(sici)1099-0534(1999)11:1<1::aid-cmr1>3.0.co;2-c

✦ Synopsis

A method for the construction of a coherence transfer diagram showing only the pathways selected by a particular phase cycle is presented. The concepts of coherences and coherence levels and their association with product operators in the spherical tensor basis are introduced. The encoding of coherence level and pulse phase information into nuclear magnetic resonance signals is described, with emphasis on the { } changes in coherence level ⌬ p produced by each of the pulses. The general requirements k which a phase cycle must satisfy in order that the coherence pathway specified by the set of { } coherence level changes ⌬ p will give rise to observable signals are developed. These k { } requirements are cast into the form of a set of congruences whose solutions are the ⌬ p . It k is shown how a coherence transfer diagram can be constructed from the phase cycle for the pulse sequence by solving this set of congruences and using rudimentary product operator analysis of the pulse sequence. The decoding of six sample pulse sequences of increasing complexity is presented.